Panel screw clinching anvil

ABSTRACT

An anvil for clinching a screw with a panel. The anvil includes an opening, a recess communicating with the opening, and raised ridges formed near the opening. When the threads of the screw are inserted through the panel and into the opening and recess of the anvil, and then a head of the screw is pressed against the panel, the ridges on the anvil deform the underside of the panel, thereby captivating the screw with the panel.

BACKGROUND

Panel screws are typically used to attach metallic sheets or panels to larger assemblies. These screws are typically inserted through holes in the panels and threaded into some sort of threaded female fastener. Sometimes it is desirable to affix the screw to the panel to improve efficiency during assembly or to prevent loss during disassembly.

One such product is the SCB Spinning Clinch Bolt, made and sold by Penn Engineering. This is a one-piece fastener that has a circular shoulder under the screw head that, when pressed into a hole in the metallic sheet, deforms the material around the hole thereby causing the hole diameter to decrease in size to smaller than the screw thread outside diameter, thus preventing the screw from being removed.

However, the SCB fastener has a specialized head configuration and is made from heat-treated steel specific for this application. Thus, the SCB fastener is not suitable for the wide variety of panel screws commonly available in the trade utilizing different head configurations and materials. Further, after installation, the SCB fastener creates an unsightly dent on the visible side of the sheet.

It would be desirable to have a system for clinching a panel screw to a panel that will work with any style screw head or material similar in hardness to the panel sheet material. Further, it would be desirable to hide any material deformation caused by such a fastener.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a clinching anvil.

FIGS. 2A-2C illustrate a sequence for using the anvil of FIG. 1 in a press.

FIGS. 3A-3J illustrate alternative embodiments of clinching anvils.

FIG. 4 illustrates a c-press.

DETAILED DESCRIPTION

Several embodiments of a clinching anvil are described. The clinching anvil is used to provide a rigid base against which a punch may be pressed. In this case, the punch is used to apply pressure to a fastener inserted into an opening in a panel against the rigid anvil. The anvil includes an opening and a recess into which the fastener moves, but also includes one or more raised ridges near the opening. When the punch is pressed down thereby forcing the fastener into the anvil recess, the ridges on the anvil deform the underside of the panel, thereby captivating the screw with the panel.

Referring now to FIG. 1, a perspective view of a clinching anvil 10 for use with panel screws is illustrated. The clinching anvil 10 is preferably formed from solid, heat-treated, lathe-turned carbon steel to be a solid body 12. Although the body is shown as a cylindrical structure in this embodiment, other shapes may be adopted. A recessed area 14 is formed coaxially inside the body 12 with a circular opening 15 in one end of the body communicating with the recessed area for receiving a fastener, such as screw 20 (see FIGS. 2A-2C) into the recessed area. A lip portion 16 is formed as an annular ring with a raised profile immediately adjacent to the opening 15 on one end of the body 12. The lip portion may comprise one or more rings or ridges having raised profiles on the end of the body 12. The raised profile of the lip portion 16 deforms the underside of a panel when pressed together with a fastener as described herein.

Referring now to FIGS. 2A-2C, a sequence for installing a screw 20 into panel 30 is illustrated.

In FIG. 2A, the screw 20 is first inserted by hand through hole 32 in panel 30 in preparation for pressing the screw into anvil 10. The hole 32 in panel 30 should be slightly larger than the outside diameter of the screw threads 21. Likewise, the opening 15 and recessed area 14 of the anvil 10 are similar in size, i.e., slightly larger than the outside diameter of screw threads 21. It should be noted that anvil 10, and in particular opening 15 and recessed area 14, can be made in a wide variety of sizes corresponding to standard or custom panel screws.

In one embodiment, a c-shaped press 50 (see FIG. 4) may be used for pressing, where the anvil 10 is held in the bottom chuck 51 of the press, and a punch 54 is held in the top chuck 52 of the press. The panel 30 is moved into position on the press 50 such that panel hole 32 aligns with the opening 15 of anvil 10, and the screw 20 is fit through opening 15 into recess 14 of anvil 10. Note in FIG. 2A that the lip 16 at the opening 15 of anvil 10 is raised in profile and therefore in position to be urged against the underside of panel 30 when the press 50 is operated. Further, the screw 20 includes a non-threaded shank portion 22 that permits axial float of the screw after installation.

The press 50 is operated by moving the top chuck 52 downward in the direction shown by arrow 53, thereby exerting pressure from the punch 54 against the head 23 of screw 20 and forcing the screw and panel 30 against the anvil 10 held in the stationary bottom chuck 51, as shown in FIG. 2B. This pressure causes the lip 16 at the opening 15 of recess 14 to deform the underside of the hole 32 in panel 30 thereby effectively reducing the size of opening 32 such that the screw threads 21 can no longer pass through the opening 32, as illustrated in FIG. 2C.

FIGS. 3A-3L illustrate alternative embodiments of the anvil.

FIGS. 3A-3B illustrate the same embodiment as shown in FIGS. 1-2, wherein the anvil 10 includes circular opening 15 and lip 16 disposed adjacent the opening 15. The lip 16 is actually an annular ridge formed to have a raised profile which comes to a sharp point at its apex approximately 0.020 inches above the surface 19 of the anvil 10. Transition portions 111, 112 are formed with the ridge 16 on either side thereof. The total width of the ridge and transition portions is approximately 0.040 inches. The raised profile of the ridge 16 deforms the underside of panel 30 when pressed.

In FIGS. 3C-3D, the anvil 210 includes opening 15, but instead of adjacent lip 16, this embodiment includes a series of discrete, straight ridges 216 disposed radially, for example, at 90 degree intervals around the opening 15. The ridges 216 are formed to have a raised profile, for example, approximately 0.020 inches high above anvil surface 19 and 0.040 inches wide, which deforms the underside of panel 30 when pressed.

In FIGS. 3E-3F, the anvil 310 includes opening 15, and an annular ridge 316 that is disposed immediately adjacent opening 15. A transition portion 317 provides a smooth transition from the top of the ridge 316 down to the surface 19 of the anvil 310. The annular ridge 316 is formed to have a raised profile which deforms the underside of panel 30 when pressed. This configuration is similar to that shown in FIGS. 3A-3B, but in this configuration, there is no transition portion between the ridge and the opening, and the raised profile of the ridge 316 is wider than that of ridge 216. For example, the ridge 316 may be 0.04 inches wide across the top of the ridge, as opposed to lip 16 in FIGS. 3A-3B, which comes to a point on top of the ridge.

In FIGS. 3G-3H, the anvil 410 includes opening 15, and an annular ridge 416 that is not disposed immediately adjacent opening 15, but is separated from the opening by a transition portions 418 and 419. Transition portion 418 provides a smooth angled transition from the top of ridge 416 down to transition portion 419. Transition portion 419 provides a smooth flat transition to the opening 15. Transition portion 417 provides a smooth angled transition from the other side of the ridge 416 down to the surface 19 of anvil 410. The raised annular profile of ridge 416 deforms the underside of panel 30 when pressed.

Finally, in FIGS. 3I-3J, the anvil 510 includes opening 15, and an annular ridge 516 disposed near the opening 15, with a transition portion 517 that provides a smooth transition from the top of ridge 516 to the opening 15. The raised profile of ridge 516 is rounded off, but still deforms the underside of panel 30 when pressed.

In general, those skilled in the art to which this disclosure relates will recognize that changes in construction and materials will suggest themselves without departing from the spirit and essential characteristics of this disclosure. Accordingly, the disclosures and descriptions herein are intended to be illustrative, and not limiting, of the scope of the invention, which is set forth in the claims. 

1. An anvil for use in captivating a screw to a panel, comprising: a solid body having an opening on one end thereof communicating with a recess, and at least one raised ridge on the one end, wherein the opening and recess are formed to be slightly larger than a diameter of the screw.
 2. The anvil of claim 1, wherein the raised ridge is formed immediately adjacent the opening.
 3. The anvil of claim 1, further comprising a transition portion formed between the raised ridge and the one end of the body.
 4. The anvil of claim 3, wherein the transition portion is formed between the raised ridge and the opening on the body.
 5. The anvil of claim 1, wherein the raised ridge is an annular ridge.
 6. The anvil of claim 1, wherein the raised ridge is a series of discrete ridges.
 7. An anvil for clinching a screw to a panel, the panel having a hole of a first diameter for receiving the screw, wherein the first diameter is slightly larger than threads of the screw, comprising: a body having a recessed portion within the body, an opening at one end of the body communicating with the recessed portion, and a raised portion on the one end of the body, wherein the opening and recessed portion are formed to have the first diameter; whereupon inserting threads of the screws through the panel and into the recessed portion of the body and then pressing a head of the screw against the panel, the raised portion of the body deforms the panel adjacent the opening thereby captivating the screw with the panel.
 8. The anvil of claim 7, wherein the body is cylindrical in shape, the recessed portion is formed coaxially within the body, and the opening is circular.
 9. The anvil of claim 7, wherein the raised portion is formed as one or more ridges.
 10. The anvil of claim 9, wherein the ridges are formed as linear structures.
 11. The anvil of claim 9, wherein the ridges are formed as annular structures surrounding a circular opening. 